Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q13/00—Waveguide horns or mouths; Slot antennas; Leaky-waveguide antennas; Equivalent structures causing radiation along the transmission path of a guided wave
  • H01Q13/10—Resonant slot antennas
  • H01Q13/18—Resonant slot antennas the slot being backed by, or formed in boundary wall of, a resonant cavity ; Open cavity antennas
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
  • H01Q5/50—Feeding or matching arrangements for broad-band or multi-band operation
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
  • H01Q9/04—Resonant antennas
  • H01Q9/0407—Substantially flat resonant element parallel to ground plane, e.g. patch antenna
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
  • H01Q9/04—Resonant antennas
  • H01Q9/0407—Substantially flat resonant element parallel to ground plane, e.g. patch antenna
  • H01Q9/0442—Substantially flat resonant element parallel to ground plane, e.g. patch antenna with particular tuning means

Definitions

• the present invention relates to the field of antenna technology. It relates to a broadband patch antenna according to the preamble of claim 1. Such an antenna is known for example from the document US-B1 -6,317,084. BACKGROUND ART In the past two decades, the applications of wireless communication technologies have exploded. This has today led to the fact that both voice and data services are transmitted in different frequency bands. For mobile voice transmission are essentially the 400, 800, 900, 1800 and 1900 MHz band available worldwide. With the introduction of the Universal Mobile Telecommunication System (UMTS) standard, the frequency range has been increased to 2170 MHz.
• UMTS Universal Mobile Telecommunication System
• the frequency range 3400-3600 MHz As an alternative to landline telephony - keyword WLL (Wireless Local Loop) - has been released in recent years in various European countries, the frequency range 3400-3600 MHz. If high data rates are to be transmitted, this can today be done wirelessly via the WLAN frequencies (Wireless Local Area Network). For these applications, the shared frequencies are in the 2.4 and 5.5 GHz range.
• WLL Wireless Local Loop
• a particularly suitable design due to its simplicity is the patch antenna mentioned in the introduction, in which a patch plate arranged above a conductive base is used as the radiator. Unlike a monopole antenna, it concentrates the radiated energy to a smaller solid angle.
• Patch antennas are described extensively in numerous documents and articles (see, for example, the "Microstrip Antenna Design Handbook," Artech House, Boston London, 2001, pages 8-9 and 16-17), which are characterized by their flat and cost-effective design
• a major drawback of patch antennas compared to other types of antennas is their narrow banding
• a patch antenna achieves bandwidth ratios of 1: 1, 2 for a VSWR (Voltage Standing Wave Ratio) of ⁇ 2. It is therefore in the Past efforts have been made to increase the bandwidth of patch antennas.
• Some of the solutions proposed for this purpose are listed and discussed in the introductory part (columns 1-3) of the cited document, but lead to comparatively complex antenna structures, without being able to completely fulfill the requirements for broadband.
• the object is solved by the entirety of the features of claim 1.
• the core of the invention is that the patch panel has the shape of a cross, and that the head of the feeder between the base of the reflector and the patch plate is formed as an inner conductor of a coaxial conductor arrangement. Due to the special cross-shaped shape of the patch plate in conjunction with the geometry of the coaxial feed an extreme broadband is achieved, so that the antenna a bandwidth ratio of 1: 3 with a VSWR (Voltage Standing Wave Ratio) of ⁇ 2 covers and at the same time very easy to implement is.
• VSWR Voltage Standing Wave Ratio
• a preferred embodiment of the broadband patch antenna according to the invention is characterized in that the patch panel from a rectangular basic form emerges in that at the four corners of the rectangle each have a rectangular recess is provided, that the patch plate is mirror-symmetrical to a center line and the Feed point lies on the center line, and that the rectangular recesses transverse to the center line (21) have the same width.
• the rectangular basic shape of the patch panel has a width of 0.58 ⁇ u and a length of O ⁇ ⁇ u
• the rectangular recesses (20a, .., d) each have a width (W2, W3 ) of 0.165 ⁇ u and a length of 0.11 ⁇ u and 0.055 ⁇ u , respectively, and when the predetermined first height (H) is 0.08 ⁇ u , where ⁇ u is the wavelength at the lower operating frequency of the antenna.
• a further preferred embodiment of the broadband patch antenna according to the invention is characterized in that the size of the base of the reflector is selected so that the vertical projection of the patch plate on the base surface is completely in the base surface, that the base surface is square, that the base of the reflector has an edge length of 0.66 ⁇ u each, where ⁇ u is the wavelength at the lower operating frequency of the antenna, that the reflector has perpendicular to the base side walls which laterally surround the patch plate, and that the height of the side walls is equal to the predetermined first Height of the patch panel is above the base of the reflector.
• the reflector and the patch plate preferably consist of a highly electrically conductive sheet metal, in particular copper, aluminum or brass, and the sheet has a thickness which is substantially greater than the penetration depth of the skin effect at the intended operating frequency.
• electrically insulating spacers are provided.
• an intermediate layer of a dielectric for example a plastic foam, can also be provided to maintain the predetermined first height of the patch plate above the base surface of the reflector.
• the patch plate is electrically short-circuited by means of electrically conductive connecting elements with the reflector.
• a further preferred embodiment of the invention is characterized in that the inner conductor is enclosed in the coaxial conductor arrangement by an electrically conductive hollow cylinder, wherein the hollow cylinder surrounds the inner conductor of the base of the reflector, starting up to a predetermined second height, which is smaller than the predetermined first height, wherein the outer diameter of the hollow cylinder is 0.052 ⁇ u , and the predetermined second height is 0.052 ⁇ u , where ⁇ u is the wavelength at the lower operating frequency of the antenna.
• FIG. 1 in plan view from above (Figure 1a) and in cross-section ( Figure 1 b) shows a preferred first embodiment of a broadband patch antenna according to the invention
• FIG. 2 shows, in a representation comparable to FIG. 1, a second exemplary embodiment of a broadband patch antenna according to the invention with distributed connecting or spacing elements between the reflector base surface and the patch plate;
• Fig. 3 in a comparable to Fig. 1 representation of a third embodiment of a broadband patch antenna according to the Invention with a dielectric intermediate layer between the reflector base and the patch plate and a protective hood.
• the broadband patch antenna 10 essentially comprises a box-shaped reflector 11 which is open to one side, a patch plate 12 arranged inside the reflector 11 with a feed point 16 and a coaxial feed device 13, 14, 15, by means of which the RF power is transmitted from the outside the patch plate 12 can be given.
• the electrically conductive reflector 11 has a rectangular, planar base surface 11 a with the width Wg and the length Lg.
• the base area merges into vertical side walls 11b, which have a uniform height Hg.
• Parallel to the base 11 a is at a height H above the base 11 a and parallel to this the flat patch plate 12 is arranged.
• the base 11a of the reflector 11 is larger than the surface of the patch plate 12, so that the vertical projection of the patch plate 12 is completely within the base 11a and the patch plate 12 has a sufficient distance from the enclosing side walls 11 b.
• the patch plate 12 has the shape of a cross with a rectangular edge contour.
• the cross shape is - starting from a rectangular basic shape with the external dimensions (W1 + W2 + W3) x (L1 + L2 + L3), whose sides are parallel to the sides of the base 11a - through rectangular recesses 20a, .., d in the Corners of the rectangle generated.
• the patch plate 12 with its recesses 20a, .., d is preferably mirror-symmetrical to a center line 21, on which the feed point 16 is arranged and can be moved to adapt the antenna properties (double arrow in Fig. 1-3).
• the recesses 20a, .., d have the dimensions (width x length) W2 x L2, W3 x L2, W3 x L3 and W2 x L3.
• the feeding point 16 has the distance Ws from the right outer edge of the patch plate 12 and the distance Ls from the lower outer edge of the patch plate 12.
• the inner conductor 14 is coaxially enclosed - starting from the base surface 11a - up to a height Hk by an electrically conductive hollow cylinder 13 with the outer diameter Dk and forms together with the hollow cylinder 13 a coaxial line.
• All materials must be electrically conductive.
• copper, aluminum or brass is used.
• the thicknesses of the parts used should be much greater than the penetration depth of the skin effect at the operating frequency. Since the reflector 11 must ensure the mechanical stability of the antenna, it is preferably made of aluminum sheet.
• the positioning of the patch plate 12 to the reflector 11 can be carried out according to FIG. 2 by distributed spacers 17 made of plastic, which support the patch plate 12 against the reflector 11.
• distributed spacers 17 made of plastic, which support the patch plate 12 against the reflector 11.
• FIG. 3 it is also conceivable, according to FIG. 3, to provide a solid intermediate layer 18 of foamed plastic or the like between the base 11a of the reflector 11 and the patch plate 12, which acts as a dielectric.
• the patch plate 12 may be connected at one or more points by means of a connecting element 17 in the form of a metallic Bolzens be electrically shorted to the reflector 11, without the electrical operation of the antenna is impaired.
• the input impedance of the antenna can be adjusted to values ⁇ 50 ohms or> 50 ohms.
• a protective hood 19 which protects the antenna elements 11 and 12 from the outside. It ensures that the electromagnetic radiation can emerge from the antenna as unhindered as possible, that persons can not touch the current-carrying metal surfaces directly and furthermore that the antenna is protected against weather and environmental influences. It is usually made of plastic and slipped over the antenna. Based on the broadband basic design shown in FIGS. 1 to 3, it goes without saying that in addition all methods known from the prior art can be used to further increase the bandwidth.
• broadband patch antenna 11 reflector 11a base (reflector) 11 b side wall (reflector) 12 patch plate 13 hollow cylinder 14 inner conductor 15 RF connector (eg SMA) 16 feed point 17 connecting element (spacer) 18 intermediate layer (dielectric, eg plastic foam) 19 protective cover 20a, .., d recess 21 center line Dk diameter H 1 Hg 1 Hk height Lg, L1, .., L3 length Wg, W1, .., W3 width

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• Waveguide Aerials (AREA)
• Aerials With Secondary Devices (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

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Citations (2)

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• 2005
  • 2005-06-07 WO PCT/CH2005/000319 patent/WO2006000116A1/de not_active Application Discontinuation
  • 2005-06-07 EP EP05744731A patent/EP1759437A1/de not_active Withdrawn
  • 2005-06-07 CN CN2005800207684A patent/CN1973404B/zh not_active Expired - Fee Related
  • 2005-06-07 BR BRPI0512416-6A patent/BRPI0512416A/pt not_active IP Right Cessation
• 2006
  • 2006-12-04 US US11/566,265 patent/US7432862B2/en not_active Expired - Fee Related

Patent Citations (2)

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